1. Field
The present disclosure describes a novel additive manufacturing method and apparatus.
2. Description of the Related Art
Conventional engine nacelle lipskins are fabricated from a single thin aluminum sheet that is either spun formed or super-plastically formed (SPF) into the desired lipskin (mostly circular) shape. Spin forming an engine nacelle lipskin involves setting a donut shaped flat sheet of metal on a mandrel having the shape of the lipskin, spinning the mandrel while heating the flat sheet so as to soften the metal, and using a stylus to apply a force to the surface the sheet so as to slowly form the sheet to the shape of mandrel. SPF forming an engine nacelle lipskin involves placing the donut shaped flat sheet of metal into a heated die so as to soften the metal, and applying pressure to one side of the sheet to stretch the sheet into the shape of the die's surface. Such metal forming processes are imprecise, do not allow fabrication of parts having variable symmetry, and make long draws especially difficult.
However, Computational Fluid Dynamics (CFD) methods can be used to optimize the external airflow surfaces to reduce drag and increase laminar flow of engine inlets. These CFD designs of much larger, complex, and non-symmetric, engine inlet shapes are difficult to form within required tolerances (high smoothness) via traditional methods such as SPF and spin forming. What is needed are methods of fabricating complex external airflow surfaces. The present disclosure satisfies this need.